1. Field of the Invention
This invention relates to an apparatus for automatically grinding surface defects in an elongate block of metallic material such as a bloom and a billet, primarily after it is hot-rolled, and more particularly, to an automatic surface defect grinding apparatus capable of automatically carrying out a longitudinal grinding for the defective surface portion of such a bloom or billet which extends in the direction of the longitudinal axis of the bloom or billet and on which a defect marking has been deposited in a defect inspecting step.
2. Description of the Prior Art
A bloom or billet is manufactured by subjecting an ingot to, for example hot-scarfing, rolling the hot-scarfed ingot and finishing it to a predetermined gauge. In course of formation of an ingot, gas holes may be produced in the peripheral surface layer of the ingot. If the gas holes remain in the surface of the ingot even after it has been hot-scarfed, they tend to be extended in rolling and thus mature into defects on the surface of the billet extending in the direction of the longitudinal axis of the billet. Furthermore, such a longitudinally extending defect may be produced on the surface of a billet in rolling due to malfunction of the rolls in rolling stands. Such defects on the surface of a billet may cause cracking in some applications of the billet and thus are extremely harmful.
Heretofore, such defects on the surface of a billet have been removed by detecting the positions of the defects on the surface of the billet, manually or automatically, applying a defect marking of chalk, paint or the like to the surface of the billet at the detected positions, and manually grinding the marked portions of the surface of the billet by means of a grinding wheel in a deseaming step. This conventional method has required too much labor for deseaming.
Thus, it is an object of this invention to provide an automatic surface defect grinding apparatus capable of automatically and efficiently grinding defective portions on an elongate block of metallic material under a completely unattended condition.